Hi I have a 2000 Hyundai Accent that has started to shake when I reach speeds of 65mph and stops at about 73 or 74 mph. This started when we had a flat driver's side tire. Our muffle just went bad and while the mechanic had the car we asked him to check out the shaking. He said he noticed it but that we need new tires and that would take care of that. Before we go out and buy new tires though I want to make sure that's all it could be. If anyone has had a similar problem your advice would be greatly appreciated! Thanks!!!